GB/T 15623.2-2003 Hydraulic transmission electrically modulated hydraulic control valves Part 2: Test methods for three-way directional flow control valves
Some standard content:
GB/T15623.2—2003
This part is compiled by modifying the international standard IS010770-2:1998 "Hydraulic drive electrically modulated hydraulic control valves Part 2: Test methods for three-way directional flow control valves", and is a revision of GB/T15623—1995. This part and GB/T15623.1-2003 abolish and replace GB/T15623-1995 "Test methods for electro-hydraulic servo valves". GB/T15623, under the general title "Hydraulic drive electrically modulated hydraulic control valves", consists of the following parts: - Part 1: Test methods for four-way directional flow control valves; - Part 2: Test methods for three-way directional flow control valves; - Part 3: Test methods for pressure control valves. This part has the following technical differences from the international standard ISO10770-2:1998: In "2 Normative References", this part replaces the international standards cited in IS010770-2:1998 with the corresponding national standards;
In "Figure 14, a)", this part replaces the "response time" in IS010772-2:1998 with "rise time"; - In ISO10770-2:1998, port A is called "control port". In order to conform to the habits of my country's hydraulic industry and to distinguish it from the concept of "pilot control port, external control port", this part changes it to "working port". - "Filtration" in Table 2 of IS010770-2:1998 is changed to "Oil Contamination Level" in this part. ", the description column is changed to *The oil contamination level should be in accordance with the use regulations of the component manufacturer, and the expression method is in accordance with GB/T14039". - ISO10770-2:1998's 8.1.2.2.3 test steps, 8.1.2.3.3 test steps keep the oil supply pressure for at least 30s", this part changes it to keep the oil supply pressure for at least 5min". The reference to Appendix C of ISO10770-2:1998 has been deleted. This part has made the following modifications to GB/T15623-1995: - This part only specifies the test methods for three-way directional flow control valves. The content of this part is more comprehensive than the previous version and has a wider scope of application. It not only includes the test methods for electro-hydraulic servo valves, but also covers electro-hydraulic proportional directional valves and electro-hydraulic proportional flow Test method for valves. The name of the standard is changed to be consistent with the name of the adopted international standard. Appendix A of this part is a normative appendix, and Appendix B is an informative appendix. This part is proposed by the China Machinery Industry Federation. This part is under the jurisdiction of the National Hydraulic and Pneumatic Standardization Technical Committee (CSBTS/TC3). Drafting units of this part: National Key Laboratory of Fluid Transmission and Control, Zhejiang University, Beijing Institute of Automation of Mechanical Industry. Main drafters of this part: Wu Genmao, Qiu Minxiu, Shang Zengwen, Liu Xinde, Zhao Manlin The previous versions of the standards replaced by this part are: --- GB/T15623--1995.
GB/T15623.2—2003
In the hydraulic transmission system, the power depends on the hydraulic power source. Pressurized fluid is transmitted to one or several loads through an electrically modulated hydraulic control valve.
This type of control valve is a component that receives an electrical control signal and obtains hydraulic power from a power source, and then controls the flow direction and flow rate of the fluid to the load according to the size and polarity of the electrical input signal. In order to successfully apply electrically modulated hydraulic control valves, it is necessary to understand many static and dynamic characteristics of this type of valve and their test methods. Scope
Hydraulic transmission electrically modulated hydraulic control valve
Part 2: Three-way directional flow control valve
Test method
GB/T15623.2—2003
This part specifies the product acceptance and type (or identification) test methods for electrically modulated hydraulic three-way directional flow control valves. 2 Normative references
The clauses in the following documents become the clauses of this part through reference in this part. For all dated referenced documents, all subsequent amendments (excluding errata) or revisions are not applicable to this part, however, parties reaching agreements based on this part are encouraged to study whether the latest versions of these documents can be used. For all undated referenced documents, the latest versions are applicable to this part. GB/T786.1 Hydraulic and pneumatic graphic symbols (eqvISO1219-1:1991) GB/T3141 ISO viscosity classification of industrial liquid lubricants (eqvISO3448:1992) GB/T4728 (all parts) Graphic symbols for electrical schematics (idtIEC617) GB/T7631.2 Classification of lubricants and related products (Class L) Part 2: Group H (Hydraulic systems) (eqvISO6743-4:1982)
GB/T14039 Code for solid particle contamination levels of hydraulic transmission oils (ISO4406:1999, MOD) GB/T17446 Terminology of fluid transmission systems and components (idtISO5598:1985) 3 Terms and definitions
The terms and definitions established in GB/T17446 and the following terms and definitions apply to this part. 3.1
Electrically modulated hydraulic flow control valves are hydraulic valves that provide proportional flow control in response to a continuously changing electrical input signal. 4 Symbols and units
The symbols and units of the characteristic parameters related to this section are listed in Table 1 Table 1 Characteristic parameter symbols and units
Characteristic parameter
Coil impedance
Coil inductance
Coil resistance
Insulation resistance
Flutter amplitude
Flutter frequency
Input signal
%Percentage of maximum input signal
GB/T15623.2 —2003
Characteristic parameters
Rated signal
Output flow
Rated flow
Flow gain
Internal leakage
Supply pressure
Return pressure
Load pressure
Valve pressure drop
Rated valve pressure drop
Pressure gain
Amplitude ratio
Phase shift
Note: 1bar=105 N/m2=0.1 MPa.
5Standard test conditions
Table 1 (continued)
IN or UN
K(8g/81 or q/8U)
PV=PpPA or PA-PT
S(8pA/81 or pA/8U)
1/min/input signal unit
%Percentage of maximum input signal
MPa(bar)
MPa(bar)
MPa(bar)
MPa(bar)
MPa(bar)
MPa(bar)/input signal unit
%Percentage of maximum input signal
degrees(°)
Unless otherwise specified, the standard test conditions given in Table 2 apply to the test tables specified in this standard. 2 Standard test conditions
Ambient temperature
Oil contamination level
Type of hydraulic oil
Hydraulic oil temperature
Hydraulic oil viscosity grade
Oil supply pressure
Oil return pressure
(20±5)℃
The oil contamination level shall be in accordance with the component manufacturer's usage regulations and the expression method shall be in accordance with GB/T14039. Mineral-based hydraulic oil sold on the market, that is, I-HL hydraulic oil specified in GB/T7631.2 or other hydraulic oil suitable for valve operation
At the valve inlet (40±6)℃
N32, in accordance with GB/T 3141
According to the corresponding test requirements, the allowable error is ±2.5% as recommended by the manufacturer
Note: When using other alternative hydraulic oils, the type and viscosity grade of the oil shall be specified. 2
6 Test equipment
6.1 Overview
GB/T 15623.2—2003
A test equipment that complies with the provisions of 6.2 and 6.3 and can meet the allowable error limits specified in Appendix A should be provided. Appendix B provides guidelines for the implementation of the test.
Note 1: Figures 1, 2 and 3 are typical test circuits. These circuits do not include all the safety devices that must be set up to prevent accidents due to component failure. Other test circuits that can achieve the same purpose can be used, but the safety measures for test personnel and test equipment must be considered. Note 2: The graphic symbols used in Figures 1, 2 and 3 should comply with the provisions of GB/T786.1 and GB/T4728. 6.2 Static test
Figure 1 shows a typical static test circuit. The test device using this circuit allows the following characteristic curves to be recorded by point-by-point or continuous plotting method:
Flow-input signal characteristic curve;
b) Pressure-input signal characteristic curve;
Flow-valve pressure drop characteristic curve;
d) Flow-load pressure characteristic curve;
e) Flow-temperature characteristic curve.
6.3 Dynamic test
Figure 2 shows a typical dynamic test circuit. This circuit uses part of the circuit in Figure 1. The test device using this circuit can perform the following tests:
a) Frequency response test;
b) Step response test.
7 Electrical test
7.1 Overview
Before carrying out subsequent tests, all valves without integrated circuits should be subjected to the tests specified in 7.2 to 7.4 as appropriate. 7.2 Coil Resistance
This test shall be conducted on the coil at the specified ambient temperature. Using an electronic measuring instrument with a measurement accuracy better than ±2% of the measured value, measure the resistance between the two ends of the valve coil.
Note: It is not necessary to supply pressurized oil to the valve under test when measuring the coil resistance. 7.3 Coil Inductance
7.3.1 Measure the total coil inductance of the valve operating under the standard test conditions specified in Table 2 (coil series that conforms to the four-lead, two-coil structure).
Note: The apparent inductance measured in this test will vary with the frequency and amplitude of the signal due to the influence of the back EMF (electrical motion force) generated by the moving armature. The test results can be used to select a suitable drive amplifier. 7.3.1.1 Connect a suitable oscillator to drive the valve coil, which needs to be connected in series with a precision non-inductive resistor (see Figure 3a).
7.3.1.2 Adjust the oscillator frequency f to 50 Hz or 60 Hz to distinguish it from the power supply frequency of the test equipment. 7.3.1.3 Adjust the input current of the valve so that its peak value is equal to the rated current of the valve. 7.3.1.4 Use an oscillator that can provide undistorted current to the valve. 7.3.1.5 Use an oscilloscope to monitor the voltage waveform of the resistor R and check whether the waveform is a sine wave. 7.3.1.6
6 Measure the peak values of the AC voltages UR, Ur and Uv. Draw the curve shown in Figure 3b) to represent the vector relationship between the voltages. 7.3. 1.7
Determine the coil impedance according to the following formula:
GB/T 15623.2—2003
Where:
Z—impedance, in ohms (2).
Where:
L—apparent inductance, in henry (H).
2 yuan f×UR
·（2）
7.3.2Another optional test method: Use the step response at full current to obtain the coil time constant t, and calculate the inductance using the following formula: L R.Xt. (As shown in Figure 4)
7.4 Insulation resistance
Apply a 500V DC voltage between the valve coil terminal and the valve body for 15s. While applying the voltage, measure the insulation resistance with a corresponding insulation tester. The current reading on the tester corresponds to the resistance, and the insulation resistance is calculated from the following formula in ohms (2):
R—500V
Where the measured current I is expressed in amperes (A). (4)
This resistance is generally more than 100MQ. In addition, for four-lead dual-turn construction, the resistance between the coils can also be determined. If the internal electrical components are in contact with the oil (such as wet coils), the valve should be filled with hydraulic oil before performing this test. 8 Performance Tests
When performing all the following tests, the amplifier specified by the valve manufacturer (when the amplifier is specified) should be included in the test system. If an external pulse width modulation amplifier is used, the modulation frequency should be recorded. In all cases, the amplifier supply voltage should be recorded. Note: All performance tests should be performed on the valve and amplifier. The input signal is applied to the amplifier, not directly to the valve. 8.1 Static Tests
8.1.1 Overview
When performing these tests, dynamic effects should be carefully excluded. Test a) should be performed first before any other tests. Pressure resistance test, according to 8.1.2;
internal leakage test, according to 8.1.3;
output flow-input signal characteristic test under constant valve pressure drop, according to 8.1.4 and 8.1.5, to determine: 1)
rated flow;
flow gain;
flow linearity;
flow hysteresis;
flow symmetry;
flow polarity;
valve core covering condition;
threshold value.
Output flow-valve pressure drop characteristic test, according to 8.1.6; d)
Limiting power characteristic test, according to 8.1.7;
Output flow or valve core position-oil temperature characteristic test, according to 8.1.8; Pressure gain-input signal characteristic test, according to 8.1.9; h) Fault protection function test, according to 8.1.10.8.1.2 Pressure resistance test
8.1.2.1 Overview
GB/T 15623.2—2003
The pressure resistance test should be carried out before other valve tests to verify the pressure resistance of the valve. A simplified high-pressure test device can be used for this test, replacing the device of the test circuit shown in Figure 1. 8.1.2.2 Oil supply pressure resistance test
During the test, the pressure resistance pressure is applied to the pressure oil port and the working oil port of the valve, and the return oil port is opened at the same time. This test should be carried out according to the following steps. 8.1.2.2.1 Test circuit
Establish the hydraulic test circuit shown in Figure 1, open valves f and i, and close all other valves. 8.1.2.2.2 Setting
Adjust the valve supply pressure to 1.3 times the rated supply pressure or 35MPa (350bar), whichever is lower. 8.1.2.2.3 Test steps
Maintain the supply pressure for at least 5min.
Apply the maximum positive input signal.
Inspect the valve for external leakage and signs of permanent deformation during the test. 8.1.2.3 Return port pressure test
During the test, the pressure resistance pressure is applied to the pressure oil port, working oil port and return oil port of the valve. The test shall be carried out as follows. 8.1.2.3.1 Test circuit
Establish the hydraulic test circuit shown in Figure 1, open valves c, d and g at the same time, and close all other valves. 8.1.2.3.2 Set
the supply pressure of the regulating valve to 1.3 times the specified maximum return port pressure. 8.1.2.3.3 Test procedure
Maintain this pressure for at least 5 min.
Apply the maximum negative input signal.
No external leakage or permanent deformation should occur during the test. 8.1.3 Internal leakage test (closed working ports) 8.1.3.1 General
Before the test, make the necessary mechanical/electrical adjustments, such as zeroing the valve. Then perform the test as follows to determine the total internal leakage including all pilot control flows. 8.1.3.2 Test circuit
Establish the hydraulic test circuit shown in Figure 1, with valve f open and all other valves closed. 8.1.3.3 Set
the supply pressure of the regulating valve to 10 MPa (100 bar) or more above the return pressure, and the applicable pilot pressure. 8.1.3.4 Test Procedure
Perform the test as follows:
a) Before conducting the leakage test, run the valve several times rapidly over the entire input signal range. b) Record the leakage at port T and port Y over the maximum positive and negative input signal ranges. If necessary, repeat these tests with the pressure increased to the rated pressure of the valve under test. 8.1.4 Output Flow-Input Signal Characteristic Test at Constant Valve Pressure Drop (Open Working Port) 8.1.4.1 OverviewWww.bzxZ.net
This test should be conducted to obtain the output flow-input signal curve and thereby obtain the steady-state characteristics of the valve. 8.1.4.2 Test circuit
For multi-stage valves with internal pilot oil supply, a circuit configuration with appropriate modifications may be used, such as any of the following methods:5
GB/T 15623.2-2003
a) Insert a pressure compensator between the valve and the test oil block; b) Use the loading valve shown in Figure 1 to load the test valve. The valve can operate under open or closed loop conditions to maintain a constant pressure drop across the valve.
8.1.4.3 Setting
8.1.4.3.1 Depending on the specific situation, set the total pressure drop of the valve to 1MPa (10bar), 7MPa (70har) or 1/3 of the maximum oil supply pressure.8.1.4.3.2 For multistage valves with independent pilot supply, adjust the pilot supply pressure to 10 MPa (100 bar). 8.1.4.3.3 For multistage valves with internal pilot supply, adjust the supply pressure to 10 MPa (100 bar), unless otherwise specified by the manufacturer. 8.1.4.4 Flow from supply port P to working port A 8.1.4.4.1 Test circuit
Establish the hydraulic test circuit shown in Figure 1, open valves a, b, d, f and i, and close all other valves. 8.1.4.4.2 Test steps
Perform the test as follows:
a) Cycle the input signal several times.
b) Use continuous plotting/recording mode to establish an appropriate coordinate system, record the input signal on the X axis and the output flow on the Y axis. Adjust the automatic signal generator to produce a triangular wave with an amplitude of zero to the maximum positive input signal. c)i
d) The input signal changes continuously and periodically, ensuring that the recording pen moves freely at a certain speed, that is, at this speed, the dynamic influence of the flow sensor and its output signal and the recorder can be ignored. When using an XY plotter or recorder, the automatic control valve must have a certain pressure drop, and it must be ensured that the change in valve pressure drop is constant within 5% during the entire signal cycle. e) While continuously applying a continuously changing signal, continuously record the characteristics within a complete signal cycle (see Figure 6) to determine the following performance characteristics when flowing from the oil supply port P to the working oil port A: 1) Output flow under rated positive signal; 2) Flow gain;
3) Linearity;
4) Hysteresis;
5) Dead zone characteristics (i.e., slide valve covering state). If necessary, the above test can be repeated with the pressure increased to the rated pressure of the test valve. 8.1.4.5 Flow from working oil port A to return oil port T 8.1.4.5.1 Test circuit
Establish the hydraulic test circuit shown in Figure 1, open valves a, d, e, h and i, and close all other valves. 8.1.4.5.2 Test steps
Perform the test as follows:
a) Cycle the input signal several times.
b) Use the continuous plotting/recording method to establish an appropriate coordinate system, record the input signal on the X axis and the output flow on the Y axis. Adjust the automatic signal generator to produce a triangular wave with an amplitude of zero to the maximum negative input signal. c
Make the input signal change continuously and periodically to ensure that the pen moves freely at a certain speed, that is, at this speed, the dynamic influence of the flow sensor and d)
its output signal and the recorder can be ignored. When using an XY plotter or recorder, the automatic control valve must have a certain pressure drop, and the change in the valve pressure drop must be constant within 5% during the entire signal cycle. While continuously applying a continuously changing signal, continuously record the characteristics during a complete signal cycle (see Figure 6) to determine the following performance characteristics when the oil flows from the working oil port A to the return oil port T: 1) Output flow under rated negative signal; Flow gain;
3) Linearity:
4) Hysteresis;
5) Dead zone characteristics (i.e. slide valve cover state); 6) Symmetry, refer to 8.1.4.4.2e)1). GB/T 15623.2—-2003
If necessary, the above test can be repeated at a pressure increase to the rated pressure of the test valve. In the event that the output flow cannot be monitored, the valve core position may be monitored instead to determine: the valve core position at the rated signal;
-hysteresis;
-polarity.
8.1.5 Valve characteristic test
8.1.5.1 Overview
This test shall be performed to obtain the valve response to a reverse input signal. 8.1.5.2 Settings
Repeat the settings described in 8.1.4.3.1, 8.1.4.3.2 and 8.1.4.3.3. 8.1.5.3 Flow from supply port P to working port A 8.1.5.3.1 Test circuit
Establish the pressure test circuit shown in Figure 1, open valves a, b, d, f and i, and close all other valves. 8.1.5.3.2 Test Procedure
Repeat steps a) and b) of 8.1.4.4.2, and then proceed as follows: a) Input a reverse signal to make the output flow (A to T) 25% of the rated flow, then reduce the input signal to reduce the flow. The input signal should be reduced slowly to eliminate dynamic effects; b) Record the input signal when the flow begins to decrease; Determine the threshold by calculating the signal change increment based on the algebraic difference between the two recorded signal values; c)
Repeat steps a) to c) at 75% of the rated flow; d)
e) Use similar tests when testing the zero position of zero opening and negative cover valves. Note: When performing these tests, the sensitivity of the recorder may need to be adjusted. See Figure 7 for a typical recording diagram. AC signal levels may be used for product acceptance tests.
8.1.5.4 Flow from working oil port A to return oil port T 8.1.5.4.1 Test circuit
Establish the hydraulic test circuit shown in Figure 1, open valves a, d, e, h and i, and close all other valves. 8.1.5.4.2 Test steps
Repeat the test steps a) and b) of 8.1.4.4.2, and then proceed as follows a) Input a reverse input signal so that the output flow (A to T) is 25% of the rated flow, and then reduce the input signal to reduce the flow. Slowly reduce the input signal to eliminate dynamic effects; b) Record the input signal when the flow begins to decrease; determine the reading by calculating the signal change increment based on the algebraic difference between the two recorded signal values; c)
d) Repeat steps a) to c) at 75% of the rated flow; e) Use similar tests when testing the zero position of zero opening and negative cover valves. Note: When performing these tests, the sensitivity of the recorder may need to be adjusted. A typical recording diagram is shown in Figure 7. AC signal levels may be used for product acceptance testing.
8.1.6 Output flow-valve pressure drop characteristic test (open working oil port) 8.1.6.1 Overview
Perform the following test steps to determine the output flow-valve pressure drop characteristic. 8.1.6.2 Setting
Adjust the supply pressure of the valve to the rated pressure. If necessary, compensate the return pressure. During the entire test, ensure that the set supply pressure is constant. A drop in supply pressure indicates insufficient flow from the hydraulic source. 8.1.6.3 Flow from port P to working oil port A 8.1.6.3.1 Test circuit
Establish the hydraulic test circuit shown in Figure 1, open valves a, b, d, f, i and loading valve 13, and close all other valves. 8.1.6.3.2 Test steps
Perform the test as follows:
a) Input the input signal gradually from zero to the maximum positive value, and repeat several times. b) Set up the XY recorder to record the output flow on the Y axis and the valve pressure drop (pp-pA) on the X axis (see Figure 8). Adjust the input signal to the rated positive value (100%).
c) Close the loading valve 13, start recording with the drawing pen, and slowly open the loading valve 13 (see Figure 1). Measure the curve of the continuous change of the output flow-valve pressure drop under the rated positive input signal. d) Repeat steps c) and d) at 75%, 50% and 25% of the rated input signal (see Figure 8). e) For valves with built-in pressure compensators, perform the above test to measure the effect of the load compensation device, and record the results using the method shown in Figure 9.
8.1.6.4 Flow from working oil port A to return oil port T 8.1.6.4.1 Test circuit
Establish the hydraulic test circuit shown in Figure 1, open valves a, d, e, h, i and loading valve 13, and close all other valves. 8.1.6.4.2 Test steps
Perform the test as follows:
a) Input the input signal gradually from zero to the maximum reverse value, and cycle several times. Set up an XY recorder to record the output flow on the Y axis and the valve pressure drop (pA-pr) on the X axis (see Figure 8) b)
Adjust the input signal to the rated reverse value (100%). c)
Close the loading valve 13, start recording with the drawing pen, and slowly open the loading valve 13 (see Figure 1), and measure the curve of the continuous change of the output flow-valve pressure drop under the rated reverse input signal. Repeat steps c) and d) at 75%, 50% and 25% of the rated input signal (see Figure 8). e)
For valves with built-in pressure compensators, perform the above test to measure the effect of the load compensation device and record its f)
results using the method shown in Figure 9.
8.1.7 Limit power characteristic test (open the working oil port) 8.1.7.1 Overview
The performance of a single-stage valve is limited by hydraulic forces. To determine these effects, the following tests should be performed. 8.1.7.2 Setting
Adjust the supply pressure, for example to 10% of the rated pressure. 8.1.7.3 Flow from supply port P to working port A 8.1.7.3.1 Test circuit
Establish the hydraulic test circuit shown in Figure 1, open valves a, b, d, f and i, and close all other valves. 8.1.7.3.2 Test steps
Set up an XY recorder, record the output flow on the Y axis, and record the valve pressure drop (Pp-PA) on the X axis, and obtain a continuous change curve of output flow-valve pressure drop.
a) Adjust the input signal to 95% of the maximum positive value, and then superimpose a low-frequency small sine signal (5%), with a typical frequency of 0.2 Hz~0.4 Hz;
b) The drawing pen starts recording;
c) Slowly increase the oil supply pressure and measure the output flow-valve pressure drop relationship curve (see Figure 10). When the sinusoidal motion is suddenly interrupted or the flow rate suddenly drops, stop increasing the oil supply pressure and mark the point on the graph;8
GB/T 15623.2—2003
d) Repeat this test at other positive input signal amplitudes, i.e. 75%, 50% and 25% of the rated flow;e) Connect those marked points (zero slope points on the curve) to obtain the limiting power characteristic curve (see Figure 10). 8.1.7.4 Flow from working oil port A to return oil port T 8.1.7.4.1 Test circuit
Establish the hydraulic test circuit shown in Figure 1, open valves a, e, d, h and i, and close all other valves. 8.1.7.4.2 Test steps
Set up an XY recorder, record the output flow on the Y axis, record the valve pressure drop (A-pr) on the X axis, and obtain a continuous change curve of the output flow-valve pressure drop.
Adjust the input signal to 95% of the reverse value, and then superimpose a low-frequency small sine signal (±5%), whose typical frequency a)
is 0. 2 Hz~0. 4 Hz;
The drawing pen starts recording;
Slowly increase the oil supply pressure and measure the flow-valve pressure drop relationship curve (see Figure 10). c) When the sinusoidal motion is suddenly interrupted or the flow rate suddenly drops, stop increasing the oil supply pressure and mark the point on the graph; d)
Repeat this test at other negative input signal amplitudes, namely 75%, 50% and 25% of the rated flow rate; e) Connect those marked points (zero slope points on the curve) to obtain the limiting power curve (see Figure 10). 8.1.8 Output flow or valve core position-oil temperature characteristic test (open working oil port) 8.1.8.1 Overview
The following test should be carried out to determine the output flow-oil temperature change characteristics. The valve and amplifier should be placed in a constant temperature environment of 20℃. 8.1.8.2 Test circuit
Establish the hydraulic test circuit shown in Figure 1, open valves a, b, d, f and i, and close all other valves. 8.1.8.3 Settings
Repeat the settings described in 8.1.4.3.
8.1.8.4 Test steps
Perform the test in the following steps:
a) Use continuous drawing/recording method to establish an appropriate coordinate system, record the fluid temperature on the X-axis, and record the output flow and/or valve core position on the Y-axis (see Figure 11);
Input a positive input signal equivalent to 10% of the rated output flow; b) Carry out
Record the relationship between output flow or valve core position and oil temperature (see Figure 11); c)
If necessary, the above test can be repeated for different input signals and valve pressure drops; d)t
e) Draw a set of curves under different input signals and valve pressure drops within the selected temperature range. 8.1.9 Pressure gain-input signal characteristic test (closed working oil port) 8.1.9.1 Overview
The purpose of this test is to determine the load pressure-input signal characteristic curve of the closed working oil port A. 8.1.9.2 Test circuit
Establish a hydraulic test circuit as shown in Figure 1, open valves f and i, and close all other valves. 8.1.9.3 Setting
Adjust the oil supply pressure to the rated pressure of the valve. 8.1.9.4 Test steps
Perform the test in the following steps:
a) Select the input signal so that the valve core has enough travel when passing through the valve neutral position so that the working oil port can effectively reach the amplitude of the oil supply pressure;
Use the continuous drawing/recording method to determine the appropriate range and deviation;b)
c) Slowly change the input signal within the range determined in item a) and record the closed oil port pressure of oil A at the same time;9
GB/T15623.2--2003
Note: Because this test is affected by the leakage characteristics of the valve and the volume of the fluid, it takes several minutes to complete a scan. d) Draw the load pressure-input signal curve of the closed oil port A (see Figure 12). 8.1.10 Fault protection function test
Perform the test in the following steps:
a) Check the inherent fault protection characteristics of the valve, such as the inherent fault protection characteristics of the valve when the input signal is lost, the electric power is lost or reduced, the hydraulic power is lost or reduced, the feedback signal is lost, etc.; b) By monitoring the valve core position, check the performance of any fault protection function device installed in the valve; c) If necessary, select a different input signal and repeat the above test. 8.2 Dynamic test (open working oil port)
8.2.1 Test circuit and settings
8.2.1.1 Establish a test circuit similar to that shown in Figure 2. 8.2.1.2 Make the length of the pipeline from oil port A to the actuator as short as possible. 8.2.1.3 Make the accumulator as close as possible to the P oil port of the valve. 8.2.1.4 Provide a constant pressure of 10 MPa (100 bar) or the rated pressure, whichever is lower. Measure the maximum output flow. 8.2.1.5 For the frequency response test, use a frequency response analyzer, oscilloscope or other suitable electronic instrument to measure the amplitude of the output signal and its phase shift relative to the input signal. For the step response test, use an oscilloscope or other electronic instrument to record the output signal-time relationship curve.
8.2.1.6 Measure the output signal by one of the following methods: a) Use the output of a speed sensor driven by a low friction (pressure drop not exceeding 0.3 MPa (3 bar) and low inertia (bandwidth at least 3 times greater than the highest test frequency including the trapped oil volume effect) actuator as the output signal. When this method is not feasible, methods b) or c) may be used.
b) For valves equipped with an internal valve core position sensor but not an internal pressure compensated flow controller, use the valve core position signal as the output signal.
If the valve does not have an internal plug position sensor and does not have an internal pressure compensated flow controller, it is necessary to install an external c)
plug position sensor and suitable signal conditioning electronics and use this signal as the output signal, provided that the additional sensor does not affect the frequency response of the valve.
Methods a), b) and c) will not give the same results. The data recorded in the test report should indicate the test method used. 8.2.2 Frequency response - test procedure
8.2.2.1 The input signal frequency is 5 Hz or 5% of the frequency at which the phase lag is 90°, whichever is less. The amplitude ratio and phase lag curves are then plotted over the bandwidth where the attenuation is greater than 15 dB (see Figure 13). If necessary, the response frequencies for 45°, 90° and higher phase lags are also included.
8.2.2.2 Test the valve under all of the following sinusoidal input signal conditions: Input a centered input signal so that the output flow through port A alternates about zero with an amplitude sufficient to produce a peak output flow of approximately ±5% of the maximum steady-state output flow. For positive-overlap valves, use a deadband eliminator for this test. a) For positive-overlap valves without a deadband eliminator, input a bias input signal so that the output flow is always in one direction, e.g., the valve core always completes a full cycle on one side of the center. b) Replace the linear actuator with a flow sensor of adequate bandwidth. Input a small signal, e.g., an input signal with an amplitude at or very close to 0 Hz, and the resulting output signal change is approximately 5% to 15% of the maximum static output signal at the supply pressure. Repeat the above test in the opposite direction. c) Repeat test a) or b) under the conditions shown in Table 3. 10And close all other valves. 8.1.7.3.2 Test steps
Set up an XY recorder, record the output flow on the Y axis, and record the valve pressure drop (Pp-PA) on the X axis to obtain the output flow-valve pressure drop continuous change curve.
a) Adjust the input signal to 95% of the maximum positive value, and then superimpose a low-frequency small sine signal (±5%), with a typical frequency of 0.2 Hz~0.4 Hz;
b) The drawing pen starts recording;
c) Slowly increase the oil supply pressure and measure the output flow-valve pressure drop relationship curve (see Figure 10). When the sinusoidal motion is suddenly interrupted or the flow rate suddenly drops, stop increasing the oil supply pressure and mark the point on the graph; 8
GB/T 15623.2—2003
d) Repeat this test at other positive input signal amplitudes, i.e. 75%, 50% and 25% of the rated flow rate; e) Connect those marked points (zero slope points on the curve) to obtain the limiting power characteristic curve (see Figure 10). 8.1.7.4 Flow from working oil port A to return oil port T 8.1.7.4.1 Test circuit
Establish the hydraulic test circuit shown in Figure 1, open valves a, e, d, h and i, and close all other valves. 8.1.7.4.2 Test steps
Set up an XY recorder, record the output flow on the Y axis, and record the valve pressure drop (A-pr) on the X axis to obtain a continuous change curve of output flow-valve pressure drop.
Adjust the input signal to 95% of the reverse value, and then superimpose a low-frequency small sine signal (±5%), with a typical frequency of 0.2 Hz~0.4 Hz;
The drawing pen starts recording;
Slowly increase the oil supply pressure and measure the flow-valve pressure drop relationship curve (see Figure 10). When the sinusoidal motion is suddenly interrupted or the flow rate suddenly drops, stop increasing the oil supply pressure and mark the point on the graph; d)
Repeat this test at other negative input signal amplitudes, i.e. 75%, 50% and 25% of the rated flow; e) Connect those marked points (zero slope points on the curve) to obtain the limit power curve (see Figure 10). 8.1.8 Output flow or valve core position-oil temperature characteristic test (open working oil port) 8.1.8.1 Overview
The following test should be carried out to determine the output flow-oil temperature change characteristics. The valve and amplifier should be placed in a constant temperature environment of 20℃. 8.1.8.2 Test circuit
Establish the hydraulic test circuit shown in Figure 1, open valves a, b, d, f and i, and close all other valves. 8.1.8.3 Setting
Repeat the setting described in 8.1.4.3.
8.1.8.4 Test steps
Perform the test in the following steps:
a) Use continuous drawing/recording method to establish an appropriate coordinate system, record the fluid temperature on the X-axis, and record the output flow and/or valve core position on the Y-axis (see Figure 11);
Input a positive input signal equivalent to 10% of the rated output flow; b) Carry out
Record the relationship between output flow or valve core position and oil temperature (see Figure 11); c)
If necessary, the above test can be repeated for different input signals and valve pressure drops; d)t
e) Draw a set of curves under different input signals and valve pressure drops within the selected temperature range. 8.1.9 Pressure gain-input signal characteristic test (closed working oil port) 8.1.9.1 Overview
The purpose of this test is to determine the load pressure-input signal characteristic curve of the closed working oil port A. 8.1.9.2 Test circuit
Establish a hydraulic test circuit as shown in Figure 1, open valves f and i, and close all other valves. 8.1.9.3 Setting
Adjust the oil supply pressure to the rated pressure of the valve. 8.1.9.4 Test steps
Perform the test in the following steps:
a) Select the input signal so that the valve core has enough travel when passing through the valve neutral position so that the working oil port can effectively reach the amplitude of the oil supply pressure;
Use the continuous drawing/recording method to determine the appropriate range and deviation;b)
c) Slowly change the input signal within the range determined in item a) and record the closed oil port pressure of oil A at the same time;9
GB/T15623.2--2003
Note: Because this test is affected by the leakage characteristics of the valve and the volume of the fluid, it takes several minutes to complete a scan. d) Draw the load pressure-input signal curve of the closed oil port A (see Figure 12). 8.1.10 Fault protection function test
Perform the test in the following steps:
a) Check the inherent fault protection characteristics of the valve, such as the inherent fault protection characteristics of the valve when the input signal is lost, the electric power is lost or reduced, the hydraulic power is lost or reduced, the feedback signal is lost, etc.; b) By monitoring the valve core position, check the performance of any fault protection function device installed in the valve; c) If necessary, select a different input signal and repeat the above test. 8.2 Dynamic test (open working oil port)
8.2.1 Test circuit and settings
8.2.1.1 Establish a test circuit similar to that shown in Figure 2. 8.2.1.2 Make the length of the pipeline from oil port A to the actuator as short as possible. 8.2.1.3 Make the accumulator as close as possible to the P oil port of the valve. 8.2.1.4 Provide a constant pressure of 10 MPa (100 bar) or the rated pressure, whichever is lower. Measure the maximum output flow. 8.2.1.5 For the frequency response test, use a frequency response analyzer, oscilloscope or other suitable electronic instrument to measure the amplitude of the output signal and its phase shift relative to the input signal. For the step response test, use an oscilloscope or other electronic instrument to record the output signal-time relationship curve.
8.2.1.6 Measure the output signal by one of the following methods: a) Use the output of a speed sensor driven by a low friction (pressure drop not exceeding 0.3 MPa (3 bar) and low inertia (bandwidth at least 3 times greater than the highest test frequency including the trapped oil volume effect) actuator as the output signal. When this method is not feasible, methods b) or c) may be used.
b) For valves equipped with an internal valve core position sensor but not an internal pressure compensated flow controller, use the valve core position signal as the output signal.
If the valve does not have an internal plug position sensor and does not have an internal pressure compensated flow controller, it is necessary to install an external c)
plug position sensor and suitable signal conditioning electronics and use this signal as the output signal, provided that the additional sensor does not affect the frequency response of the valve.
Methods a), b) and c) will not give the same results. The data recorded in the test report should indicate the test method used. 8.2.2 Frequency response - test procedure
8.2.2.1 The input signal frequency is 5 Hz or 5% of the frequency at which the phase lag is 90°, whichever is less. The amplitude ratio and phase lag curves are then plotted over the bandwidth where the attenuation is greater than 15 dB (see Figure 13). If necessary, the response frequencies for 45°, 90° and higher phase lags are also included.
8.2.2.2 Test the valve under all of the following sinusoidal input signal conditions: Input a centered input signal so that the output flow through port A alternates about zero with an amplitude sufficient to produce a peak output flow of approximately ±5% of the maximum steady-state output flow. For positive-overlap valves, use a deadband eliminator for this test. a) For positive-overlap valves without a deadband eliminator, input a bias input signal so that the output flow is always in one direction, e.g., the valve core always completes a full cycle on one side of the center. b) Replace the linear actuator with a flow sensor of adequate bandwidth. Input a small signal, e.g., an input signal with an amplitude at or very close to 0 Hz, and the resulting output signal change is approximately 5% to 15% of the maximum static output signal at the supply pressure. Repeat the above test in the opposite direction. c) Repeat test a) or b) under the conditions shown in Table 3. 10And close all other valves. 8.1.7.3.2 Test steps
Set up an XY recorder, record the output flow on the Y axis, and record the valve pressure drop (Pp-PA) on the X axis to obtain the output flow-valve pressure drop continuous change curve.
a) Adjust the input signal to 95% of the maximum positive value, and then superimpose a low-frequency small sine signal (±5%), with a typical frequency of 0.2 Hz~0.4 Hz;
b) The drawing pen starts recording;
c) Slowly increase the oil supply pressure and measure the output flow-valve pressure drop relationship curve (see Figure 10). When the sinusoidal motion is suddenly interrupted or the flow rate suddenly drops, stop increasing the oil supply pressure and mark the point on the graph; 8
GB/T 15623.2—2003
d) Repeat this test at other positive input signal amplitudes, i.e. 75%, 50% and 25% of the rated flow rate; e) Connect those marked points (zero slope points on the curve) to obtain the limiting power characteristic curve (see Figure 10). 8.1.7.4 Flow from working oil port A to return oil port T 8.1.7.4.1 Test circuit
Establish the hydraulic test circuit shown in Figure 1, open valves a, e, d, h and i, and close all other valves. 8.1.7.4.2 Test steps
Set up an XY recorder, record the output flow on the Y axis, and record the valve pressure drop (A-pr) on the X axis to obtain a continuous change curve of output flow-valve pressure drop.
Adjust the input signal to 95% of the reverse value, and then superimpose a low-frequency small sine signal (±5%), with a typical frequency of 0.2 Hz~0.4 Hz;
The drawing pen starts recording;
Slowly increase the oil supply pressure and measure the flow-valve pressure drop relationship curve (see Figure 10). When the sinusoidal motion is suddenly interrupted or the flow rate suddenly drops, stop increasing the oil supply pressure and mark the point on the graph; d)
Repeat this test at other negative input signal amplitudes, i.e. 75%, 50% and 25% of the rated flow; e) Connect those marked points (zero slope points on the curve) to obtain the limit power curve (see Figure 10). 8.1.8 Output flow or valve core position-oil temperature characteristic test (open working oil port) 8.1.8.1 Overview
The following test should be carried out to determine the output flow-oil temperature change characteristics. The valve and amplifier should be placed in a constant temperature environment of 20℃. 8.1.8.2 Test circuit
Establish the hydraulic test circuit shown in Figure 1, open valves a, b, d, f and i, and close all other valves. 8.1.8.3 Setting
Repeat the setting described in 8.1.4.3.
8.1.8.4 Test steps
Perform the test in the following steps:
a) Use continuous drawing/recording method to establish an appropriate coordinate system, record the fluid temperature on the X-axis, and record the output flow and/or valve core position on the Y-axis (see Figure 11);
Input a positive input signal equivalent to 10% of the rated output flow; b) Carry out
Record the relationship between output flow or valve core position and oil temperature (see Figure 11); c)
If necessary, the above test can be repeated for different input signals and valve pressure drops; d)t
e) Draw a set of curves under different input signals and valve pressure drops within the selected temperature range. 8.1.9 Pressure gain-input signal characteristic test (closed working oil port) 8.1.9.1 Overview
The purpose of this test is to determine the load pressure-input signal characteristic curve of the closed working oil port A. 8.1.9.2 Test circuit
Establish a hydraulic test circuit as shown in Figure 1, open valves f and i, and close all other valves. 8.1.9.3 Setting
Adjust the oil supply pressure to the rated pressure of the valve. 8.1.9.4 Test steps
Perform the test in the following steps:
a) Select the input signal so that the valve core has enough travel when passing through the valve neutral position so that the working oil port can effectively reach the amplitude of the oil supply pressure;
Use the continuous drawing/recording method to determine the appropriate range and deviation;b)
c) Slowly change the input signal within the range determined in item a) and record the closed oil port pressure of oil A at the same time;9
GB/T15623.2--2003
Note: Because this test is affected by the leakage characteristics of the valve and the volume of the fluid, it takes several minutes to complete a scan. d) Draw the load pressure-input signal curve of the closed oil port A (see Figure 12). 8.1.10 Fault protection function test
Perform the test in the following steps:
a) Check the inherent fault protection characteristics of the valve, such as the inherent fault protection characteristics of the valve when the input signal is lost, the electric power is lost or reduced, the hydraulic power is lost or reduced, the feedback signal is lost, etc.; b) By monitoring the valve core position, check the performance of any fault protection function device installed in the valve; c) If necessary, select a different input signal and repeat the above test. 8.2 Dynamic test (open working oil port)
8.2.1 Test circuit and settings
8.2.1.1 Establish a test circuit similar to that shown in Figure 2. 8.2.1.2 Make the length of the pipeline from oil port A to the actuator as short as possible. 8.2.1.3 Make the accumulator as close as possible to the P oil port of the valve. 8.2.1.4 Provide a constant pressure of 10 MPa (100 bar) or the rated pressure, whichever is lower. Measure the maximum output flow. 8.2.1.5 For the frequency response test, use a frequency response analyzer, oscilloscope or other suitable electronic instrument to measure the amplitude of the output signal and its phase shift relative to the input signal. For the step response test, use an oscilloscope or other electronic instrument to record the output signal-time relationship curve.
8.2.1.6 Measure the output signal by one of the following methods: a) Use the output of a speed sensor driven by a low friction (pressure drop not exceeding 0.3 MPa (3 bar) and low inertia (bandwidth at least 3 times greater than the highest test frequency including the trapped oil volume effect) actuator as the output signal. When this method is not feasible, methods b) or c) may be used.
b) For valves equipped with an internal valve core position sensor but not an internal pressure compensated flow controller, use the valve core position signal as the output signal.
If the valve does not have an internal plug position sensor and does not have an internal pressure compensated flow controller, it is necessary to install an external c)
plug position sensor and suitable signal conditioning electronics and use this signal as the output signal, provided that the additional sensor does not affect the frequency response of the valve.
Methods a), b) and c) will not give the same results. The data recorded in the test report should indicate the test method used. 8.2.2 Frequency response - test procedure
8.2.2.1 The input signal frequency is 5 Hz or 5% of the frequency at which the phase lag is 90°, whichever is less. The amplitude ratio and phase lag curves are then plotted over the bandwidth where the attenuation is greater than 15 dB (see Figure 13). If necessary, the response frequencies for 45°, 90° and higher phase lags are also included.
8.2.2.2 Test the valve under all of the following sinusoidal input signal conditions: Input a centered input signal so that the output flow through port A alternates about zero with an amplitude sufficient to produce a peak output flow of approximately ±5% of the maximum steady-state output flow. For positive-overlap valves, use a deadband eliminator for this test. a) For positive-overlap valves without a deadband eliminator, input a bias input signal so that the output flow is always in one direction, e.g., the valve core always completes a full cycle on one side of the center. b) Replace the linear actuator with a flow sensor of adequate bandwidth. Input a small signal, e.g., an input signal with an amplitude at or very close to 0 Hz, and the resulting output signal change is approximately 5% to 15% of the maximum static output signal at the supply pressure. Repeat the above test in the opposite direction. c) Repeat test a) or b) under the conditions shown in Table 3. 102—2003
d) Repeat this test at other positive input signal amplitudes, namely 75%, 50% and 25% of the rated flow rate; e) Connect those marked points (zero slope points on the curve) to obtain the limiting power characteristic curve (see Figure 10). 8.1.7.4 Flow from working oil port A to return oil port T 8.1.7.4.1 Test circuit
Establish the hydraulic test circuit shown in Figure 1, open valves a, e, d, h and i, and close all other valves. 8.1.7.4.2 Test steps
Set up an XY recorder, record the output flow on the Y axis, and record the valve pressure drop (A-pr) on the X axis to obtain a continuous change curve of output flow-valve pressure drop.
Adjust the input signal to 95% of the reverse value, and then superimpose a low-frequency small sine signal (±5%), with a typical frequency of 0.2 Hz~0.4 Hz;
The drawing pen starts recording;
Slowly increase the oil supply pressure and measure the flow-valve pressure drop relationship curve (see Figure 10). When the sinusoidal motion is suddenly interrupted or the flow rate suddenly drops, stop increasing the oil supply pressure and mark the point on the graph; d)
Repeat this test at other negative input signal amplitudes, i.e. 75%, 50% and 25% of the rated flow; e) Connect those marked points (zero slope points on the curve) to obtain the limit power curve (see Figure 10). 8.1.8 Output flow or valve core position-oil temperature characteristic test (open working oil port) 8.1.8.1 Overview
The following test should be carried out to determine the output flow-oil temperature change characteristics. The valve and amplifier should be placed in a constant temperature environment of 20℃. 8.1.8.2 Test circuit
Establish the hydraulic test circuit shown in Figure 1, open valves a, b, d, f and i, and close all other valves. 8.1.8.3 Setting
Repeat the setting described in 8.1.4.3.
8.1.8.4 Test steps
Perform the test in the following steps:
a) Use continuous drawing/recording method to establish an appropriate coordinate system, record the fluid temperature on the X-axis, and record the output flow and/or valve core position on the Y-axis (see Figure 11);
Input a positive input signal equivalent to 10% of the rated output flow; b) Carry out
Record the relationship between output flow or valve core position and oil temperature (see Figure 11); c)
If necessary, the above test can be repeated for different input signals and valve pressure drops; d)t
e) Draw a set of curves under different input signals and valve pressure drops within the selected temperature range. 8.1.9 Pressure gain-input signal characteristic test (closed working oil port) 8.1.9.1 Overview
The purpose of this test is to determine the load pressure-input signal characteristic curve of the closed working oil port A. 8.1.9.2 Test circuit
Establish a hydraulic test circuit as shown in Figure 1, open valves f and i, and close all other valves. 8.1.9.3 Setting
Adjust the oil supply pressure to the rated pressure of the valve. 8.1.9.4 Test steps
Perform the test in the following steps:
a) Select the input signal so that the valve core has enough travel when passing through the valve neutral position so that the working oil port can effectively reach the amplitude of the oil supply pressure;
Use the continuous drawing/recording method to determine the appropriate range and deviation;b)
c) Slowly change the input signal within the range determined in item a) and record the closed oil port pressure of oil A at the same time;9
GB/T15623.2--2003
Note: Because this test is affected by the leakage characteristics of the valve and the volume of the fluid, it takes several minutes to complete a scan. d) Draw the load pressure-input signal curve of the closed oil port A (see Figure 12). 8.1.10 Fault protection function test
Perform the test in the following steps:
a) Check the inherent fault protection characteristics of the valve, such as the inherent fault protection characteristics of the valve when the input signal is lost, the electric power is lost or reduced, the hydraulic power is lost or reduced, the feedback signal is lost, etc.; b) By monitoring the valve core position, check the performance of any fault protection function device installed in the valve; c) If necessary, select a different input signal and repeat the above test. 8.2 Dynamic test (open working oil port)
8.2.1 Test circuit and settings
8.2.1.1 Establish a test circuit similar to that shown in Figure 2. 8.2.1.2 Make the length of the pipeline from oil port A to the actuator as short as possible. 8.2.1.3 Make the accumulator as close as possible to the P oil port of the valve. 8.2.1.4 Provide a constant pressure of 10 MPa (100 bar) or the rated pressure, whichever is lower. Measure the maximum output flow. 8.2.1.5 For the frequency response test, use a frequency response analyzer, oscilloscope or other suitable electronic instrument to measure the amplitude of the output signal and its phase shift relative to the input signal. For the step response test, use an oscilloscope or other electronic instrument to record the output signal-time relationship curve.
8.2.1.6 Measure the output signal by one of the following methods: a) Use the output of a speed sensor driven by a low friction (pressure drop not exceeding 0.3 MPa (3 bar) and low inertia (bandwidth at least 3 times greater than the highest test frequency including the trapped oil volume effect) actuator as the output signal. When this method is not feasible, methods b) or c) may be used.
b) For valves equipped with an internal valve core position sensor but not an internal pressure compensated flow controller, use the valve core position signal as the output signal.
If the valve does not have an internal plug position sensor and does not have an internal pressure compensated flow controller, it is necessary to install an external c)
plug position sensor and suitable signal conditioning electronics and use this signal as the output signal, provided that the additional sensor does not affect the frequency response of the valve.
Methods a), b) and c) will not give the same results. The data recorded in the test report should indicate the test method used. 8.2.2 Frequency response - test procedure
8.2.2.1 The input signal frequency is 5 Hz or 5% of the frequency at which the phase lag is 90°, whichever is less. The amplitude ratio and phase lag curves are then plotted over the bandwidth where the attenuation is greater than 15 dB (see Figure 13). If necessary, the response frequencies for 45°, 90° and higher phase lags are also included.
8.2.2.2 Test the valve under all of the following sinusoidal input signal conditions: Input a centered input signal so that the output flow through port A alternates about zero with an amplitude sufficient to produce a peak output flow of approximately ±5% of the maximum steady-state output flow. For positive-overlap valves, use a deadband eliminator for this test. a) For positive-overlap valves without a deadband eliminator, input a bias input signal so that the output flow is always in one direction, e.g., the valve core always completes a full cycle on one side of the center. b) Replace the linear actuator with a flow sensor of adequate bandwidth. Input a small signal, e.g., an input signal with an amplitude at or very close to 0 Hz, and the resulting output signal change is approximately 5% to 15% of the maximum static output signal at the supply pressure. Repeat the above test in the opposite direction. c) Repeat test a) or b) under the conditions shown in Table 3. 102—2003
d) Repeat this test at other positive input signal amplitudes, namely 75%, 50% and 25% of the rated flow rate; e) Connect those marked points (zero slope points on the curve) to obtain the limiting power characteristic curve (see Figure 10). 8.1.7.4 Flow from working oil port A to return oil port T 8.1.7.4.1 Test circuit
Establish the hydraulic test circuit shown in Figure 1, open valves a, e, d, h and i, and close all other valves. 8.1.7.4.2 Test steps
Set up an XY recorder, record the output flow on the Y axis, and record the valve pressure drop (A-pr) on the X axis to obtain a continuous change curve of output flow-valve pressure drop.
Adjust the input signal to 95% of the reverse value, and then superimpose a low-frequency small sine signal (±5%), with a typical frequency of 0.2 Hz~0.4 Hz;
The drawing pen starts recording;
Slowly increase the oil supply pressure and measure the flow-valve pressure drop relationship curve (see Figure 10). When the sinusoidal motion is suddenly interrupted or the flow rate suddenly drops, stop increasing the oil supply pressure and mark the point on the graph; d)
Repeat this test at other negative input signal amplitudes, i.e. 75%, 50% and 25% of the rated flow; e) Connect those marked points (zero slope points on the curve) to obtain the limit power curve (see Figure 10). 8.1.8 Output flow or valve core position-oil temperature characteristic test (open working oil port) 8.1.8.1 Overview
The following test should be carried out to determine the output flow-oil temperature change characteristics. The valve and amplifier should be placed in a constant temperature environment of 20℃. 8.1.8.2 Test circuit
Establish the hydraulic test circuit shown in Figure 1, open valves a, b, d, f and i, and close all other valves. 8.1.8.3 Setting
Repeat the setting described in 8.1.4.3.
8.1.8.4 Test steps
Perform the test in the following steps:
a) Use continuous drawing/recording method to establish an appropriate coordinate system, record the fluid temperature on the X-axis, and record the output flow and/or valve core position on the Y-axis (see Figure 11);
Input a positive input signal equivalent to 10% of the rated output flow; b) Carry out
Record the relationship between output flow or valve core position and oil temperature (see Figure 11); c)
If necessary, the above test can be repeated for different input signals and valve pressure drops; d)t
e) Draw a set of curves under different input signals and valve pressure drops within the selected temperature range. 8.1.9 Pressure gain-input signal characteristic test (closed working oil port) 8.1.9.1 Overview
The purpose of this test is to determine the load pressure-input signal characteristic curve of the closed working oil port A. 8.1.9.2 Test circuit
Establish a hydraulic test circuit as shown in Figure 1, open valves f and i, and close all other valves. 8.1.9.3 Setting
Adjust the oil supply pressure to the rated pressure of the valve. 8.1.9.4 Test steps
Perform the test in the following steps:
a) Select the input signal so that the valve core has enough travel when passing through the valve neutral position so that the working oil port can effectively reach the amplitude of the oil supply pressure;
Use the continuous drawing/recording method to determine the appropriate range and deviation;b)
c) Slowly change the input signal within the range determined in item a) and record the closed oil port pressure of oil A at the same time;9
GB/T15623.2--2003
Note: Because this test is affected by the leakage characteristics of the valve and the volume of the fluid, it takes several minutes to complete a scan. d) Draw the load pressure-input signal curve of the closed oil port A (see Figure 12). 8.1.10 Fault protection function test
Perform the test in the following steps:
a) Check the inherent fault protection characteristics of the valve, such as the inherent fault protection characteristics of the valve when the input signal is lost, the electric power is lost or reduced, the hydraulic power is lost or reduced, the feedback signal is lost, etc.; b) By monitoring the valve core position, check the performance of any fault protection function device installed in the valve; c) If necessary, select a different input signal and repeat the above test. 8.2 Dynamic test (open working oil port)
8.2.1 Test circuit and settings
8.2.1.1 Establish a test circuit similar to that shown in Figure 2. 8.2.1.2 Make the length of the pipeline from oil port A to the actuator as short as possible. 8.2.1.3 Make the accumulator as close as possible to the P oil port of the valve. 8.2.1.4 Provide a constant pressure of 10 MPa (100 bar) or the rated pressure, whichever is lower. Measure the maximum output flow. 8.2.1.5 For the frequency response test, use a frequency response analyzer, oscilloscope or other suitable electronic instrument to measure the amplitude of the output signal and its phase shift relative to the input signal. For the step response test, use an oscilloscope or other electronic instrument to record the output signal-time relationship curve.
8.2.1.6 Measure the output signal by one of the following methods: a) Use the output of a speed sensor driven by a low friction (pressure drop not exceeding 0.3 MPa (3 bar) and low inertia (bandwidth at least 3 times greater than the highest test frequency including the trapped oil volume effect) actuator as the output signal. When this method is not feasible, methods b)
Tip: This standard content only shows part of the intercepted content of the complete standard. If you need the complete standard, please go to the top to download the complete standard document for free.